Waldenström's
macroglobulinemia (WM) is a rare lymphoid
neoplasia, accounting for 2% of all
hematological malignancies. Renal complications occur rather rarely compared to
multiple myeloma. The most common renal manifestations are mild
proteinuria and microhematuria. We describe a case of MW presenting with
acute renal failure and NS. A 67-year-old man was referred to our hospital for sudden onset
nephrotic syndrome. Electrophoresis revealed a monoclonal component in the gamma region, which was classified as an
IgM k. During hospitalization,
acute kidney injury developed, with
creatinine up to 5 mg/dL, despite adequate hydration and alkalinization. A kidney biopsy was performed, showing
minimal change disease (MCD) with interstitial and capsular lymphoid infiltrates of B-Lymphocytes CD20+. B-lymphocytes infiltration suggested the possibility of renal localization of
lymphoproliferative disorder. So, bone marrow histology was performed, revealing lymphoplasmacytic
lymphoma (WM). The patient was treated with
bortezomib, desamethasone, and
rituximab, with partial recovery of renal function (
creatinine 1.5 mg/dL) and complete remission of
proteinuria after 8-month follow-up. The remission of NS in our patient with
rituximab seems to emphasize the pathogenetic role of B cells in MCD, although a coincident effect of immunosuppression on both the underlying renal disease and the
hematologic disease cannot be excluded.